An airplane is powered by one or more propulsive shipsets each comprising a turbojet engine housed in a tubular nacelle. Each propulsive shipset is attached to an aircraft by an engine strut generally located under a wing or at the fuselage.
A nacelle generally has a structure comprising an air inlet upstream of the engine and a central section capable to surround a turbojet engine fan, a downstream section housing thrust inverter means and capable to surround the combustion chamber of the turbojet engine. The nacelle is generally completed by an exhaust nozzle the output of which is located downstream of the turbojet engine.
The air inlet comprises, on the one hand, an inlet lip capable to allow optimal uptake towards the turbojet engine necessary air for the supply of the fan and internal compressors of the turbojet engine, and on the other hand, a downstream structure, onto which is mounted the lip, intended to properly channel the air towards the fan blades. The shipset is attached upstream of a fan casing belonging to the section upstream of the nacelle.
During flight, according to the temperature and humidity conditions, ice may be formed on the nacelle at the outer surface of the air inlet lip. Presence of ice or frost modifies the aerodynamic properties of the air intake and disrupts the airflow towards the fan.
One solution to deice and defrost the outer surface consists to prevent that ice from forming on this outer surface by taking hot air from the compressor of the turbojet engine and directing it up to the air Inlet lip in order to heat the walls.
In document U.S. Pat. No. 4,688,745, a nacelle 10 is proposed comprising an air intake structure 12 having a deicing compartment 13. The air intake structure 12 is capable of being mounted upstream of a central structure 14.
In order to ensure the deicing of the air inlet structure 12, a hot air supply device in the shape of a supply tube 15 conveys hot air taken from the central structure 14 towards the deicing compartment 13.
The deicing compartment 13 is delimited by:                an outer wall 16 incorporating a lip, capable to be mounted to move with respect to the said central structure 14 between an operating position and a maintenance position;        by the term “operating position” it is intended the configuration of the air intake structure wherein the aircraft is capable to fly and by “maintenance position” it is intended the configuration of the structure wherein maintenance on the air input structure can be achieved; and        an upstream partition 18.        
In order to form the elbowed supply tube, a rectilinear tube is first inserted through an orifice in the upstream partition 18, the orifice being of a size equal to the diameter of the said pipe. Then, the free end 19 present in this deicing compartment 13 is elbowed up to an angle equal to 90° with respect to the main axis 20 of the rectilinear tube. The sealing between the supply tube 15 and the upstream partition 18 is provided by a circular shape contact plate 21.
Nevertheless, besides the complexity of implementation of this supply device, the junction area between the upstream partition 18 and the elbowed supply tube 15 does not have a good sealing. As a result, hot air escapes from the deicing compartment 13 thereby damaging some equipment in the area of the central structure 14, sensitive to heat.
In patent application FR07/07049, a hot air supply device is proposed wherein the hot air is circulated by means of a supply tube connected to a manifold (so-called “piccolo”). The manifold is mounted integral on the partition.
Nevertheless, most of the forces due to pressure of the hot air conveyed into the supply tube exercises on the manifold, and hence on the partition, and on the air intake structure, which weaken the latter
Moreover, it will be observed that these prior art devices are not adapted at all to a device of the LFC (“Laminar Forward Cowl”) type such as described in patent application FR0608599 filed by the plaintiff, whereby are faced sealing problems between air intake moving parts (air intake lip integrated into the air intake outer panel) and air intake fixed parts (hot air supply+various equipment).